Influence of carbon flux on FAS outputs. (A) Total production and average length of fatty acids generated by modeled FASs (1 μM of each Fab, 10 μM TesA, 10 μM holo-ACP, 1 mM NADPH, 1 mM NADH, and 0.5 mM acetyl-CoA, 12.5 min) with varying concentrations of malonyl-CoA. As concentrations of malonyl-CoA increase, production levels increase gradually, while average length increases abruptly over a narrow range of concentrations. (B) Enhanced production levels correlate with an increase in initiation events; average chain length, with an increase in the ratio of elongation to initiation events (i.e., the relative activities of FabF and FabH on malonyl-ACP).